.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
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.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sat Jul 24 19:11:11 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified 2004-11-12 as per suggestion by Fabian Kreutz/AEB
.\"	to note that this function is not available in glibc2.
.\"
.TH INFNAN 3  1993-06-02 "GNU" "Linux Programmer's Manual"
.SH NAME
infnan \- deal with infinite or not-a-number (NaN) result
.SH SYNOPSIS
.nf
.B #include <math.h>
.sp
.BI "double infnan(int " error );
.fi
.sp
Link with \fI\-lm\fP.
.SH DESCRIPTION
The
.BR infnan ()
function returns a suitable value for infinity and
"not-a-number" (NaN) results.
The value of
.I error
can be
.B ERANGE
to represent infinity or anything else to represent NaN.
.I errno
is also set.
.SH RETURN VALUE
If
.I error
is
.B ERANGE
(Infinity),
.B HUGE_VAL
is returned.
.PP
If
.I error
is
.RB \- ERANGE
(\-Infinity),
.RB \- HUGE_VAL
is returned.
.PP
If
.I error
is anything else, NAN is returned.
.SH ERRORS
.TP
.B EDOM
The value of
.I error
is "not-a-number" (NaN).
.TP
.B ERANGE
The value of
.I error
is positive infinity or negative infinity.
.SH CONFORMING TO
4.3BSD.
.SH NOTES
This obsolete function was provided in
libc4 and libc5, but is not available in glibc2.
